CENTRAL-NERVOUS-SYSTEM TUBERCULOSIS - MRI

The MRI findings of 18 proven cases of central nervous system (CNS) tu berculosis were reviewed; 10 patients were seropositive for HIV. All h ad medical, laboratory, or surgical proof of CNS tuberculosis. Eleven patients had meningitis, of whom two also had arachnoiditis. Five pati ents had focal intra-axial tuberculomas: four brain masses and one an intramedullary spinal lesion. Two patients had focal extra-axial tuber culomas: one in the pontine cistern, and one in the spine. In all 11 p atients with meningitis MRI showed diffuse, thick, meningeal enhanceme nt. All intraparenchymal tuberculomas showed low signal intensity on T 2-weighted images and ring or nodular enhancement. The extra-axial tub erculomas had areas isointense or hypointense relative to normal brain and spinal cord on T2-weighted images. Although tuberculous meningiti s cannot be differentiated from other meningitides on the basis of MR findings, intraparenchymal tuberculomas show characteristic T2 shorten ing, not found in most other space-occupying lesions. In the appropria te clinical setting, tuberculoma should be considered.